Luis Díez de Aux y Armendáriz (Quito, c. 1571 - Barcelona, 3 January 1627) was a Spanish churchman and politician.
His elder brother was Lope Díez de Armendáriz, who would become 1st Marquess of Cadreita and Viceroy of New Spain.
Luis moved to Spain and became a Cistercian monk in the monastery of Valparaíso de Zamora.
In 1613 the Duke of Lerma appointed him abbot of the monastery of Santa María de la Oliva in Navarra, thanks to his brother's services to the Crown.
He was bishop of Jaca in 1618[1] and Urgell in 1622,[2] and as such was co-prince of Andorra along with King Louis XIII of France.